Core B: Summary/Abstract The Clinical Resource Core (CRC; Core B) will provide support for Projects II and III of the University of Michigan (U-M) Udall Center through recruitment, enrollment, and detailed clinical assessment of Parkinson disease (PD) patients and age- and gender-matched normal control (NC) subjects. A unique feature of the proposed U-M Udall Center renewal is that it will leverage the unique deeply clinical and neuroimaging phenotyped PD population from our current Udall Center. The cohort of PD patients comprehensively assessed in the current U-M Udall Center cycle will be recruited for additional longitudinal assessments with a supplemental cohort of new PD disease subjects. The CRC has standardized methods for data collection, entry, and verification, as developed by the Biostatistics and Data Management Core (BDMC; Core D), which are in compliance with HIPAA and IRB regulations. Data collected is consistent with NINDS Common Data Elements to facilitate transfer of data to the NINDS Data Management Repository. The CRC will closely collaborate with the Neuroimaging Resource Core (NRC; Core C) to coordinate in vivo neuroimaging assessments of subjects. The CRC will serve as the liaison between Project III and the investigators of the Dutch Parkinson and Cognition (DUPARC) study at the University of Groningen (P.I. Dr. Teus van Laar). The CRC will continue to foster existing collaborations with the Pacific Udall (P.I. Dr. Thomas Montine) and the University of Rochester Udall (P.I. Dr. Ray Dorsey) Centers. The specific goals of the CRC are: 1. To recruit, enroll, and retain PD patients and age- and gender-matched NC subjects for the U-M Udall Center Projects II and III in support of their scientific goals. 2. To comprehensively assess all subjects with well-established clinical, motor function, and neuropsychological instruments. 3. To provide the organizational structure and operations oversight for the U-M Udall Center Projects II and III and interact and coordinate with other Cores to assure prompt neuroimaging assessment (NRC) and data transfer and analysis (BDMC). 4. Facilitate and coordinate data transfer from the University of Groningen DUPARC study. 5. Support existing collaborations with other Udall Centers and facilitate transfer of data to and from these Udall Centers.